What is Modem ?
A modem is a hardware device that allows a computer to send and receive data over a telephone line or a cable or satellite connection.
Modem : Modulate --> Digital to Analog conversionDemodulate --> Analog to Digital conversion.
An analog signal is a continuous wave that changes over a time period. It is represented by a sine wave and it has no fixed range. It transmit data in the form of a wave.The human voice is the best example of an analog signal.
A digital signal is a discrete wave that carries information in binary form. It is represented by square waves and it has a finite range i.e. 0 and 1.Signals used for transmission in a computer are the digital signal. computer understands only digital signals So, modem is a bridge between analog and digital signals.
Dail-Up Modems : It use standard telephone lines to transmit and receive information. Dialup modems were the only kind of modems out there for years.
- Internal : It is part of the chipset on the motherboard and also available as separate expansion cards. The advantage of an internal modem is that it doesn’t take up any desk space, it uses the PC’s internal power supply, and it’s always on.
- External : It requires a separate power supply. The advantages of an external modem are you can manually turn the modem off when it acts stubborn.
Broadband Modems : It connect to the Internet at top speeds. The only downsides to broadband modems are that you must live in an area that provides broadband service.
- Cable : It is faster then DSL if consumers are more then speed will decrease.
- DSL (Digital Subscriber Line) : It gives you fast access by taking advantage of unused frequencies in existing phone lines. Next to cable, DSL gives you the fastest connection speeds.
- Satellite : Combined with an outdoor antenna and a subscription to the satellite service, this is one of the fastest modem options available but some devices that include only a demodulator (and no modulator, thus only allowing data to be downloaded by satellite).
